New Studies Examine the Significant Risk of Life

NEWS RELEASE
UNDER EMBARGO UNTIL APRIL 28, 2015, 1:30 PM PT
For more information contact:
Nicole Baritot
Managing Editor, AATS Scientific Publications
American Association for Thoracic Surgery
500 Cummings Center, Suite 4550
Beverly, MA 01915 USA
+1 978-299-4520
[email protected]
www.aats.org
New Studies Examine the Significant Risk of Life-Threatening Blood Clots in
Post-Surgical Lung Cancer Patients
Presentations at the 95th AATS Annual Meeting Present Data on the Incidence of VTEs Underscore
the Importance of Screening and Proactive Treatment and Use
of an Effective Risk Assessment Tool
One life-threatening complication of lung cancer surgery is the formation of blood clots in the lungs (also
called pulmonary embolism - PE) or in the legs (also known as deep vein thrombosis - DVT). Together,
they would be defined as venous thromboembolic events (VTE). Several presentations at AATS 2015
shed new light on this serious problem. In the first prospective study of its kind, the incidence of VTE was
found to be higher than previously reported, with a 5.4% VTE-specific mortality rate. Of concern to
clinicians, most events were asymptomatic and occurred after patients were discharged from the hospital.
The second report highlights the importance of screening for VTEs, especially since the majority of lower
extremity VTEs found after pneumonectomy would have gone undiagnosed and untreated without
screening. The third report describes a risk assessment tool for VTEs that is applied for the first time to
predict an individual’s risk of VTEs after lung cancer surgery, which can help clinicians decide whether
prolonged anti-clotting therapy is warranted.
Seattle, WA, April 28, 2015 – New evidence suggests that lung cancer surgery patients are at higher risk
of developing venous thromboembolism, including deep vein thrombosis (DVT) and pulmonary embolism
(PE), than previously thought, with elevated risks of complications or death. When thromboemboli occur,
they may be asymptomatic or attributed to post-surgical pain or complications, and may reflect both the
lung cancer itself as well as compromised lung function after surgery. These incidents may also be
ascribed to an inconsistent approach to prevention that currently exists among thoracic surgeons and
hematologists who care for these patients. Three presentations at the 95th Annual Meeting of the
American Association for Thoracic Surgery explore the problem of venous thromboembolism (VTE) after
surgery for lung cancer.
Symptoms of PE include breathing difficulties that begin suddenly, rapid breathing, rapid heart rate, chest
pain, cough, coughing up blood, fainting, and sense of impending doom. Common symptoms of DVT are
lower-extremity swelling, localized warmth and tenderness, fever, and cyanosis. The effects of VTE range
from mild to life-threatening.
In the first report, Yaron Shargall, MD, who is Head of the Division of Thoracic Surgery and holds the
Juravinski Professorship in Thoracic Surgery at McMaster University (Hamilton, ON), and colleagues from
McMaster University (Hamilton) and the University of Toronto will present the results of the first
prospective analysis of the incidence of VTE following oncologic lung resection as part of the General
Thoracic Surgery Moderated Poster Competition. This study, funded by the Heart and Stroke Foundation
of Canada, looked at outcomes for 157 patients who underwent thoracic surgery for primary lung cancer
(89.9%) or metastatic cancer (6.3%). All patients received blood thinners (unfractionated heparin or low
molecular weight heparin) and mechanical VTE preventative treatment (graduated compression
stockings) from the time of surgery until leaving the hospital.
Two weeks later, these patients were evaluated for the presence of VTE signs and symptoms. Clinical
outcomes were evaluated at 30±5 days post-operatively using CT pulmonary angiography and bilateral
Doppler venous ultrasonography. Patients who had developed symptoms suggestive of VTE within the 30
days after surgery underwent urgent CT-PE examination, and a repeat scan 30-days postoperatively if
the first scan was negative. Patients with VTE were monitored and treated.
In this group among patients considered to be at high risk of VTE because of their lung cancer,
investigators found 19 VTE events, a 12.1% incidence rate. These included 14 PEs (8.9%), three DVTs
(1.9%) and one combined PE/DVT. One patient developed a massive left atrial thrombus originating from
a surgical stump, and died. For all 157 patients, the 30-day mortality rate was 0.64% but 5.2% for those
who had a VTE. “This demonstrates the clinical importance and relative fatality of VTE following lung
cancer surgery,” explained Dr. Shargall.
All those diagnosed with a VTE had undergone anatomic resections (lobectomy or segmentectomy) and
most had primary lung cancer. The clots tended to form on the same side as the lung surgery. The
majority developed lung clots without forming DVTs beforehand. The investigators examined factors that
might distinguish those who developed clots from those who did not, and could not find differences in
age, lung function, hospital length of stay, comorbidities, lung cancer stage, smoking status or Caprini
Score (a score correlating to each patient’s risk of developing VTE post-operatively).
Among patients diagnosed with a VTE, only 4 (21.1%) showed symptoms. All the events were diagnosed
after the patient left the hospital and only because the patients were screened for VTEs as part of the
study. “This study shows that a significant proportion of lung cancer surgery patients are at risk of VTE,
and indicates a need for future research into minimizing the occurrence of DVT and PE. It is possible that
extended use of blood thinners beyond hospital discharge may reduce the number of patients who
experience these life-threatening events and may help to reduce the rates of death after lung surgery,”
stated Dr. Shargall.
In a related study, researchers from the Cleveland Clinic studied the effects of post-operative screening
on rates of VTEs. During the General Thoracic Surgery Simultaneous Scientific Session, Siva Raja MD,
PhD will report on the incidence of VTEs in 112 patients who underwent surgical removal of the lung
(pneumonectomy) for benign and malignant indications, who were screened for these complications and
compared them to rates of a previously published group of 336 similar patients who did not undergo VTE
screening.
The researchers found that the percentage of in-hospital VTEs in the screened group was almost threetimes higher than those not screened (8.9% vs. 3.0%) and more than twice as high during the 30-day
postoperative period (13% vs. 5.0%). In the screened group, 10 of 112 patients had VTE detected by
screening just before discharge and four additional patients developed symptomatic VTE within 30 days
despite a negative pre-discharge screen. The risk of VTEs peaks six days after surgery.
At the Cleveland Clinic, routine screening for VTE after pneumonectomy prior to discharge was adopted
in 2006. “We find that a large proportion (50%) of VTEs occurred prior to the time of discharge, and the
risk of developing symptomatic VTE remained elevated for 30 days. It is possible that the prevalence of
VTE may be even higher should a comprehensive serial screening program be initiated,” noted lead
investigator Siva Raja, MD, PhD, of the Heart and Vascular Institute, Department of Thoracic and
Cardiovascular Surgery, at the Cleveland Clinic.
VTEs are a particular problem after pneumonectomy, since these patients often have low pulmonary
reserve to withstand the impact of PE, commented Dr. Raja. Indeed, this study also showed that postpneumonectomy patients who develop VTE face a higher risk of death than those who do not. For this
reason, Dr. Raja suggests that these patients be given blood thinner medications for a longer duration, as
well as undergo repeat screening test for VTE even after discharge.
A third presentation addresses the crucial question of how to identify post-surgical lung cancer patients
who are at greatest risk of developing a VTE. In a poster presentation that is part of the General Thoracic
Surgery Modified Poster Competition, Virginia R. Litle, MD, Associate Professor of Surgery, Boston
University School of Medicine, will demonstrate that the Caprini Risk Assessment Model can be used to
stratify post-surgical lung cancer patients according to VTE risk.
“The Caprini Risk Assessment Model (RAM) is used as a VTE risk assessment tool in other surgical
specialties, including general, vascular and plastic surgery as well as gynecologic oncology, noted Dr.
Litle. “In abdominal and pelvic cancer patients, the RAM helps physicians evaluate extended prophylactic
use of blood thinners, but it has not been applied in thoracic surgery.”
The Caprini RAM is made up of about 40 risk factors, including open surgery, history of VTE, central
venous access, BMI ≥ 30, and malignancy. Based on the Caprini score, patients may be categorized into
moderate (≤4), high (5-8) and highest (>9) VTE risk groups.
In this retrospective chart review of 232 patients who underwent lung resection from 2005-2013, the 60day postoperative VTE incidence was 5.17% (12/232). Six of the 12 patients had a PE.
The mean Caprini score for those who developed VTEs was significantly higher than the mean score for
those who did not have VTEs (11.83 ± 3.74 vs. 8.07 ± 2.84, p< .001). The incidence of VTEs was 0% in
the low-to-moderate Caprini score group, 1.67% in the high Caprini score group, and 10.42% for those
with the highest Caprini scores. The one death from a PE was patient whose score fell within the highest
Caprini score group (16). When 9 was used as the cutoff for highest risk, the RAM had an 80% sensitivity,
60.9% specificity, and 61.2% accuracy.
More than 90% of VTEs occurred in patients who had undergone open thoracotomy. Because minimallyinvasive video-assisted thoracoscopic surgery did not seem to impact a patient’s risk of VTE, the
researchers recommended that it should not be added as new variable in the Caprini RAM.
“This is the first study to demonstrate the predictive ability of the Caprini RAM in post-operative lung
resection patients,” said Dr. Litle. “This risk assessment scoring system can be used to determine which
lung resection patients may potentially benefit from preventive blood thinner therapy after discharge. We
have measured these scores and found that a prolonged course of enoxaparin sodium (Lovenox) or other
blood thinners may improve the risk of dying of this complication after a lung cancer operation.”
# # #
NOTES FOR EDITORS
For more information contact Nicole Baritot, Managing Editor, AATS Scientific Publications, at +1 978299-4520 or [email protected].
“The incidence and burden of venous thromboembolism after major lung resection: A prospective cohort
analysis,” by Yaron Shargall, Waël C. Hanna, Colin Schieman, Christian J. Finley, Laura Schneider, Terri
Schnurr, John Agzarian, Dennis Nguyen-Do, Yury Peysakhovich, Thomas K. Waddell, Marc de Perrot, Lori-
Ann Linkins, Mark Crowther, James Douketis. Presentation at the 95th AATS Annual Meeting. April 25-29,
2015. Seattle, WA, during the General Thoracic Surgery Moderated Poster Competition on April 28, 1:25
PM PT. http://aats.org/annualmeeting
Journalists wishing to interview Dr. Shargall may contact him at 905-522-1155 x33229 or
[email protected]. The presentation abstract is located at http://aats.org/annualmeeting/ProgramBooks/2015/P33.cgi.
“Routine venous thromboembolism screening after pneumonectomy: The harder you look, the more you
find,” by Siva Raja, MD, PhD, Jay J. Idrees, MD, Eugene H. Blackstone, MD, Jiayan He, ScD, Peter
Mazzone, MD, MPH, David P. Mason, MD, Thomas W. Rice, MD, Daniel P. Raymond, MD, Heather L.
Gornick, MD, Sudish C. Murthy, MD, PhD. Presentation at the 95th AATS Annual Meeting. April 25-29,
2015. Seattle, WA, during the General Thoracic Surgery Simultaneous Scientific Session on April 27,
3:55 PM PT. http://aats.org/annualmeeting
Journalists wishing to interview Dr. Raja may contact him at 216-704-1347 (cell) or [email protected]. The
presentation abstract is located at http://aats.org/annualmeeting/Program-Books/2015/23.cgi.
“Caprini risk assessment for postoperative venous thromboembolism in surgical lung cancer patients,” by
Krista J. Hachey, Phillip D. Hewes, Liam P. Porter, Doug G. Ridyard, Pamela Rosenkranz, David
McAnemy, Hiran C. Fernando, Virginia R. Litle. Presentation at the 95th AATS Annual Meeting. April 2529, 2015. Seattle, WA, during the General Thoracic Surgery Moderated Poster Competition on April 28,
1:30 PM PT. http://aats.org/annualmeeting
Journalists wishing to interview Dr. Litle may contact her at 617-638-5600 or
[email protected]<mailto:[email protected]. The presentation abstract is located at
http://aats.org/annualmeeting/Program-Books/2015/P34.cgi.
These three presentations comprise the General Thoracic Deep Dive Session, April 27, 3:20-3:55 PM PT,
moderated by Keith S. Naunheim and Sidharta P. Gangadharan. Deep Dive Sessions allow the audience
and a panel of experts to take a deeper look into studies through discussion and questions.
ABOUT THE AMERICAN ASSOCIATION FOR THORACIC SURGERY (AATS)
The American Association for Thoracic Surgery (AATS) is an international organization of over 1,300 of
the world’s foremost thoracic and cardiothoracic surgeons, representing 41 countries. AATS encourages
and stimulates education and investigation into the areas of intrathoracic physiology, pathology and
therapy. Founded in 1917 by a respected group of the last century’s earliest pioneers in the field of
thoracic surgery, the AATS’ original mission was to “foster the evolution of an interest in surgery of the
Thorax.”
One hundred years later, the AATS continues to be the premiere association among cardiothoracic
surgeons. The purpose of the Association is the continual enhancement of the ability of cardiothoracic
surgeons to provide the highest level of quality patient care. To this end, the AATS encourages,
promotes, and stimulates the scientific investigation and study of cardiothoracic surgery. Visit
www.aats.org.